1. The Field of the Invention
This invention generally relates to food dispensing systems. More particularly, this invention relates to food dispensing systems for dispensing foods for immediate consumption which are served in a frozen or semifrozen form such as ice cream, sherbet, frozen yogurt and the like.
2. The Prior Art
For many years frozen foods such as ice cream have been a favorite food in many parts of the world. Restaurants and other food serving establishments regularly offer a selection of frozen foods to their customers. In addition to ice cream, other frozen foods include sherbet, sorbet, ices, and other frozen desserts. For purposes of convenience, the term "ice cream" is used throughout this disclosure; however, unless it is understood otherwise from the context, that term shall include other frozen foods as discussed above. Ice cream has become so popular that ice cream stores and other establishments emphasizing the sale of ice cream and related foods have become commonplace.
In the food service industry, two general types of ice cream are available. The first type is "hard" ice cream. Hard ice cream is ice cream which when kept at an appropriate temperature for serving remains in a relatively solid form. Hard ice cream is generally the preferred choice among consumers of ice cream. However, due to its "hard" nature, it is often difficult for a commercial establishment to conveniently serve. Hard ice cream is inconvenient to serve due to the fact that a significant amount of manual labor is required to properly remove the hard ice cream from the storage container and place it in a serving receptacle.
In order to avoid the inconvenience encountered when serving hard ice cream, many establishments offer to their customers what is termed "soft" ice cream. This type of ice cream may be easily dispensed by a machine because it is kept in a semisolid state which allows it to be easily extruded and placed in a serving receptacle by a machine.
Dispensing ice cream by using a machine offers significant advantages over manual methods; nevertheless, consumers of ice cream generally prefer hard ice cream over soft ice cream. Thus, establishments which serve ice cream have previously been faced with the decision of pleasing customers by serving hard ice cream, with its attendant labor costs and inconvenience, or by offering their customers soft ice cream with its accompanying benefit of mechanized dispensing.
Ice cream serving establishments have been faced with many problems when using manual methods to serve hard ice cream. For example, typically the containers which hold hard ice cream are kept in a horizontal freezer holding many open ice cream containers with each ice cream container usually holding several gallons. The freezer doors must be opened each time the ice cream is accessed. The constant opening of the freezer by employees makes regulation of the ice cream temperature difficult. As the temperature of the ice cream varies the consistency and quality also varies.
Furthermore, if the temperature of the ice cream is too high, harmful bacterial growth may be encouraged. The danger of bacterial growth is of such great concern to health and food inspection agencies, that strict rules and regulations regarding the serving of ice cream and other frozen foods have been promulgated. Such regulations often mandate a maximum temperature at which ice cream may be stored.
In an effort to comply with state regulations and to allow for warming of the ice cream due to frequent access to the ice cream containers, some establishments serving ice cream maintain their ice cream at a temperature far below the desired temperature, thereby causing the ice cream to be excessively hard. The result is that "scooping" (i.e., serving) of the ice cream by employees is a difficult and fatiguing task. Alternatively, some establishments keep their ice cream above the desired temperature so as to make "scooping" of the ice cream easier. While maintaining ice cream at a temperature above the desired temperature makes serving the ice cream easier, it may also degrade the quality of the ice cream and promote undesirable growth of bacteria. In addition to these problems, horizontal freezers generally require an increased amount of energy, and thus expense, in order to keep the ice cream below the maximum allowable temperature.
A further problem is that the "horizontal freezer" method of storing and serving ice cream presents the potential of creating unsanitary conditions. Since employees are constantly bending over the open ice cream containers, as well as the open containers, in some cases, being accessible to customers, a potential hazard exists from the accidental contamination of the ice cream by foreign objects. This contamination problem is increased in establishments utilizing the "hand scoop" method of serving the ice cream. Still another problem faced by establishments utilizing the "hand scoop" method of serving ice cream is that of maintaining consistency in the amount of ice cream provided from serving to serving. All of these problems have lead to efforts in the past to provide a workable and efficient mechanized system for dispensing ice cream.
One previous attempt to mechanize the dispensing of hard ice cream is disclosed in U.S. Pat. No. 2,201,403, where a motorized ice cream scoop is used. The scoop is substantially hemispherically-shaped with its bottom end closed except for an oval opening. The scoop is mounted on the shaft of a hand-held motor so that the scoop spins about its axis. While the scoop is spinning it is pushed into the ice cream which is collected into the scoop through the oval opening in the bottom of the scoop. The scoop may then be opened to dispense the ice cream. While the motorized scoop approach provides for easier scooping of the ice cream and more consistent portion sizes, it still requires extensive manual labor to serve hard ice cream and does not eliminate the problems inherent in the "open freezer" method of storing ice cream.
Another approach to solving the problems described above is disclosed in U.S. Pat. No. 3,590,750. This patent discloses a machine for making ice cream cone size portions of hard ice cream in which an open container of ice cream is mounted on a turntable and rotated. A scoop is lowered into the rotating container of ice cream until sufficient ice cream has been collected in the scoop. The scoop is then withdrawn, and the ice cream delivered to a location outside of the machine for service to the consumer. While this approach initially appears to have some practical advantages, implementing this approach in a practical dispensing system appears to be very complex, difficult, and unreliable for use in a commercial establishment which requires consistent performance.
Another attempt to provide a mechanized ice cream dispensing system is shown in U.S. Pat. No. 2,719,494, which shows a device utilizing a piston to force a volume of hard ice cream from a container, through a tube and into a receiving scoop. Once the scoop is filled, the scoop is rotated to form a ball of ice cream which is then placed in a serving receptacle. Likewise, U.S. Pat. No. 4,420,948 discloses a similar arrangement in which a piston forces a volume of hard ice cream from a horizontally disposed container, through a tube, then into a double scoop apparatus. Previous attempts at providing an extrusion-type ice cream dispenser, such as shown in U.S. Pat. Nos. 2,719,494 and 4,420,948, have met with disappointing results. Several major problems exist with these "extrusion-type" systems.
First, none of the previous attempts recognized the fact that the "hardness" of ice cream (or other frozen foods) at a particular temperature is determined by the ingredients used in the frozen food. Thus, not only do frozen foods such as sherbets and ice creams vary in their hardness at a particular temperature, but particular flavors of each type of frozen food may have significant variations in hardness at any particular temperature. Unfortunately, the "extrusion-type" dispensers of frozen foods can only operate properly when the hardness of the frozen food is within certain parameters. For example, chocolate, strawberry, and vanilla ice cream all kept at 0.degree. F. have significant differences in their hardness. Furthermore, due to the fact that various manufacturers of ice cream use widely differing ingredients, the hardness of one manufacturer's chocolate ice cream at a particular temperature may be different than the hardness of any other manufacturer's chocolate ice cream at the same temperature. The prior attempts at producing a frozen-food dispenser suitable for dispensing hard ice cream, and other similar frozen foods, have not recognized that various flavors of the same type of frozen food, particularly various frozen desserts such as ice cream, behave differently from one another at the same temperature. The fact that frozen foods vary in hardness presents a problem when attempting to design a frozen food dispenser which can accommodate a variety of frozen foods.
Second, the prior attempts have not recognized the related subtlety encountered when handling frozen foods, i.e., that the temperature at which a frozen food should be maintained differs according to what is to be done with the food. As an example, consider the case of "Brand X vanilla hard ice cream." The temperature at which the ice cream should be kept for long-term storage might ideally be -40.degree. F. to -20.degree. F. However, the temperature at which the ice cream may be kept for short-term storage, say less than three days, is preferably about +5.degree. F. This short-term storage temperature is set so that the ice cream will maintain its flavor, consistency, and texture for the expected storage period, but yet take considerably less time to reach the appropriate serving temperature (as discussed below) than from its long-term storage temperature. Finally, Brand X vanilla hard ice cream may be desirably served at a temperature of from about +10.degree. F. to about +12.degree. F.
The recognition of these factors when dealing with frozen foods, particularly ice cream, is notably absent from the earlier teachings in the art. Still further, when designing a dispensing system for frozen foods, these temperatures are critical, and the system must provide a means for adjusting and maintaining the temperature of the frozen food to the proper temperature within very narrow tolerances. This requirement is also notably absent from the earlier teachings in the art.
Third, previous attempts at "extrusion-type" ice cream dispensing systems (such as U.S. Pat. No. 2,719,494 and No. 4,420,948) do not teach the importance of properly applying pressure to the ice cream as it is extruded. The devices shown in these patents make it appear a simple matter to continuously apply sufficient pressure to the ice cream to force it through a given length of tube. In practice, such is not the case in a working frozen food dispensing system.
The pressure applied to the frozen food in the extrusion process must be precisely controlled, both by the method used to apply the pressure and by the path through which the frozen food travels. This characteristic is in opposition to the teachings of U.S. Pat. No. 4,420,948, which teaches constant pressure on a volume of frozen food through a tubular member.
All of the above considerations, which have remained unrecognized in the prior art, are essential to the design of a workable frozen food dispenser. In view of the problems discussed above, it would be a great improvement in the art to provide a mechanized frozen food dispensing system wherein the quality of the frozen food is maintained from storage to serving of the frozen food. It would also be a significant advancement in the art to provide a frozen food dispenser which protects the frozen food from unsanitary conditions, and which inhibits the growth of undesirable microorganisms. It would also be a significant improvement in the art to provide a frozen food dispensing system which greatly reduces the manual effort required to serve frozen foods while achieving the other above-mentioned benefits. The present invention recognizes all of the above-mentioned considerations and provides a practical frozen food dispensing system.